#!/bin/ksh
# @(#) rename.ksh 1.3 95/01/23
# 90/06/01 John DuBois (spcecdt@armory.com)
# 91/02/25 Improved help info
# 92/06/07 remove quotes from around shell pattern as required by new ksh
# 94/05/10 Exit if no globbing chars given.
# 95/01/23 Allow file set to be given on command line.

lname=${0##*/}
Usage="Usage: $lname [-htv] oldpattern newpattern [filename ...]"
tell=false
verbose=false

while getopts :htv opt; do
    case $opt in
    h)
	echo \
"$lname: rename files by changing parts of filenames that match a pattern.
$Usage
oldpattern and newpattern are subsets of sh filename patterns (the only
globbing characters (wildcards) allowed are ? and *).  All files that match
oldpattern will be renamed with the filename characters that match the constant
(non-globbing) characters of oldpattern changed to the corresponding constant
characters of newpattern.  The characters of the filename that match the
globbing characters of oldpattern will be preserved.  Globbing characters in
oldpattern must occur in the same order in newpattern; for every globbing
character in newpattern there must be an identical globbing character in
oldpattern in the same sequence.  Both arguments should be quoted since
globbing characters are special to the shell.  If filenames are given, only the
named files are acted on; if not, all files that match oldpattern are acted on.
Examples:
rename \"/tmp/foo*.ba.?\" \"/tmp/new*x?\"
All files in /tmp that match foo*.ba.? will have the \"foo\" part replaced by
\"new\" and the \".ba.\" part replaced by \"x\".  For example,
/tmp/fooblah.ba.baz would be renamed to /tmp/newblahxbaz
rename \* \*- foo bar baz
foo, bar, and baz will be renamed to foo-, bar-, and baz-.
Options:
-h: Print this help.
-v: Show the file move commands being executed.
-t: Show what file moves would be done, but do not execute them."
	exit 0
	;;
    t)
	tell=true
	;;
    v)
	verbose=true
	;;
    +?)
	print -u2 "$lname: options should not be preceded by a '+'."
	exit 1
	;;
    :) 
	print -r -u2 -- \
	"$lname: Option '$OPTARG' requires a value.  Use -h for help."
	exit 1
	;;
    ?) 
	print -u2 "$lname: $OPTARG: bad option.  Use -h for help."
	exit 1
	;;
    esac
done
 
# remove args that were options
let OPTIND=OPTIND-1
shift $OPTIND

oldpat=$1
newpat=$2

case $# in
[01])
    print -u2 "$Usage\nUse -h for help."
    exit 1
    ;;
2)
    set -- $1
    if [[ ! -a $1 ]]; then
	echo "No files match $oldpat."
	exit
    fi
    ;;
*)
    shift 2
    ;;
esac

typeset -i i=1 j

# For old ksh
# while [[ "$oldpat" = *'[\*\?]'* ]]; do

# Example oldpat: foo*.a
# Example newpat: bar*.b

# Examples given for first iteration (in the example, the only interation)
while [[ "$oldpat" = *[\*\?]* ]]; do
    # Get leftmost globbing pattern in oldpat
    pat=${oldpat#*[\*\?]}	# pat=.a
    pat=${oldpat%%"$pat"}	# pat=foo*
    pat=${pat##*[!\?\*]}	# pat=*
    # Find parts before & after pattern
    oldpre[i]=${oldpat%%"$pat"*}	# oldpre[1]=foo
    oldsuf[i]=${oldpat#*"$pat"}		# oldsuf[1]=.a
    newpre[i]=${newpat%%"$pat"*}	# newpre[1]=bar
    # Get rid of processed part of patterns
    oldpat=${oldpat#${oldpre[i]}"$pat"}	# oldpat=.a
    newpat=${newpat#${newpre[i]}"$pat"}	# newpat=.b
    let i=i+1
done

if [ i -eq 1 ]; then
    print -u2 "No globbing chars in pattern."
    exit 1
fi

oldpre[i]=${oldpat%%"$pat"*}	# oldpre[2]=.a
oldsuf[i]=${oldpat#*"$pat"}	# oldsuf[2]=.a
newpre[i]=${newpat%%"$pat"*}	# newpre[2]=.b

if $verbose; then
    j=1
    while [[ j -le i ]]; do
	echo \
"Old prefix: ${oldpre[j]}   Old suffix: ${oldsuf[j]}   New prefix: ${newpre[j]}"
	let j=j+1
    done
fi

# Example file: foox.a

for file; do
    j=1
    origname=$file	# origname=foox.a
    newfile=
    while [[ j -le i ]]; do
	# Peel off a prefix	interation	1		2
	file=${file#${oldpre[j]}}		# file=x.a	file=
	# Save the part of this prefix that is to be retained
	const=${file%${oldsuf[j]}}		# const=x	const=
	newfile=$newfile${newpre[j]}$const	# newfile=barx	newfile=barx.b
	file=${file#$const}			# file=.a	file=.a
	let j=j+1
    done
    if $tell; then
	echo "Would move: $origname -> $newfile"
    else
	if $verbose; then
	    echo "Moving: $origname -> $newfile"
	fi
	mv $origname $newfile
    fi
done